Issue 635 — Report URLs with a nonexistent tplan_id: graceful info page instead of E_WARNING + HTTP 500

Issue: https://github.com/sebiboga/testlink-upgraded/issues/635 Related: #634 (valid plan without builds still fatals — separate, open), #630 (resultsGeneral tprojOpt warnings — separate, open)

Symptom

Any report controller that goes through initArgsForReports() with a nonexistent tplan_id in the query string emitted an E_WARNING and died with a raw HTTP 500 / blank page:

E_WARNING
Trying to access array offset on null - in lib/results/displayMgr.php - Line 72

Repro (measured 2026-08-23, localhost:8082, PHP 8.3.33): login admin/admin → GET /lib/results/resultsByTSuite.php?tplan_id=999999&tproject_id=1&format=0 → HTTP:500 bytes:0, events table row id 2 log_level 2 with the message above.

Approach

Root cause chain:

1. lib/results/displayMgr.php:70-71 (GUI branch of initArgsForReports()) calls $tplanMgr->get_by_id($args->tplan_id); testplan::get_by_id() (lib/functions/testplan.class.php:437) returns null when no row matches.
2. Line 72 immediately reads $tplan['testproject_id'] — offset access on null → E_WARNING.
3. $args->tproject_id stays null; the guard at lines 75-78 throws "Invalid Test Project ID" which no caller catches → uncaught exception → blank 500. Fixing only the warning would have left the fatal, so both were addressed.

Fix (minimal, 2 files):

• lib/results/displayMgr.php: null-check $tplan before the offset read; on miss render the purpose-built helper displayInfo(lang_get('error_print_doc_title'), lang_get('error_print_doc_missing_testplan')) (lib/functions/info.inc.php:29) and exit.
  • Strings are pre-existing localized keys (locale/en_GB/strings.txt:641-642); lang_get() auto-falls back to en_GB in locales lacking them (lib/functions/lang_api.php:78-87) — no locale bundle edits needed.
  • One shared function ⇒ all 7 controllers inherit the fix: neverRunByPP, testAutomationSpec, resultsTC, resultsByTSuite, execTimelineStats, baselinel1l2, resultsGeneral.
  • Alternatives rejected: guard reordering only (still a raw 500); per-controller handling (7× duplication); navigator redirect (needs a valid plan context anyway).
• gui/templates/dashio/workAreaSimple.tpl: optional-link block {if $link_to_op ne ''} → {if isset($link_to_op) && $link_to_op ne ''}. Reviving displayInfo() exposed that this template had never been rendered under PHP 8.3 strictness: each render wrote 2 E_WARNINGs per request (Undefined array key "link_to_op" + Attempt to read property "value" on null for $hint_text). Guarding at the template kills it for every future caller of the helper.

Verification (6/6 PASS — see tmp/TLU_Test_Cases.md suite 635)

• Poisoned URL ×7 controllers + absent-id case: all HTTP 200 friendly info page; zero recurrences of the original warning.
• Valid plan (SQL fixture project 9001 / plan 9002 / build 9003): reports still render normally (HTTP 200, "Metrics by Level 1 & Level 2 Test Suites").
• Event Viewer: after the template fix, zero new Error/Warning rows from this path; browser pass shows the page below with an empty console.

Commits: 97f01db27 (displayMgr guard), c773394ba (template null-safety).